1. The Field of the Invention
The present invention is concerned with improvements in and relating to forensic identification, particularly where based on DNA profiling.
2. The Relevant Technology
DNA profiling offers a versatile identification technique for a wide variety of applications including, anthropological, paternity and other forensic environments. The use of such profiling is significant in determining links, or their absence, between samples. Such samples might include those taken from known individuals and/or those taken from the scene of or linked to a crime.
DNA profiling based on the use of short tandem repeats (STR) or micro satellite loci is used in such applications. STR's are a class of polymorphic markers which consist of simple tandomly repeated sequences of between 1 and 6 base pairs in length. STR's in the non-coding part of the genome are generally considered.
In the human genome STR's occur every 6 to 10 kilo bases along the DNA. The length, however, varies greatly between individuals due to mutation and provides identifying characteristics as a result.
A variety of DNA profiling systems exist, including single locus analysis and multiple locus analysis where a number of STR loci are simultaneously amplified.
In analysing the results from an unknown sample it is generally considered against a ladder marker consisting of alleles derived from actual samples. The allelic ladder provides a reference point and allows correspondence of alleles to be identified clearly.